This polar filter......

Kodachromeguy said:

Thousands of used linear polarizer are for sale on the 'bay, often quite cheap.

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When the price of linear polarizers first became quite cheap, I bought a few because I have no problem using them on my medium format and large format manual focus cameras that did not have built-in light meters.

shutterfinger said:

Circular polarizing filters came into existence shortly after auto focus was introduced. AF systems have difficulty or will not focus through linear polarizing filters but will through circular polarizing filters. Circular polarizing filters do not have as strong effect as linear polarizing filters.
What brand is your filter?

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Not true, Canon F1's came out in March 1971 and it needed a circular polarizer because the focusing screens used a beam splitter in it to divide the light between the prism and the light meter, that was about fourteen years before the first autofocus S.L.R the Minolta X7000.that needed a circular polarizer.

I am not having much luck with using this filter
When you screw it on, and then try to use it.....it never hits the "Stop".
It just keeps going and then (pretty quickly) rotates off of the threads.
It does not matter if i screw it on rather tight.....or leave it a bit loose... it always wants to come off the front of the lens.

benjiboy said:

Not true, Canon F1's came out in March 1971 and it needed a circular polarizer because the focusing screens used a beam splitter in it to divide the light between the prism and the light meter, that was about fourteen years before the first autofocus S.L.R the Minolta X7000.that needed a circular polarizer.

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Even earlier, 1969, the Pentacon LLC. At least, it is a candidate, I have to check the meter on this.

CMoore said:

I am not having much luck with using this filter
When you screw it on, and then try to use it.....it never hits the "Stop".
It just keeps going and then (pretty quickly) rotates off of the threads.
It does not matter if i screw it on rather tight.....or leave it a bit loose... it always wants to come off the front of the lens.

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The grease has hardened. Thus all you do is screwing the filter on and off. Of course that does not make the filter usesless, but it always is on the rim of falling off.
Take it apart and subsitute the grease for fresh one.

CMoore said:

It is Nikon branded.
What seems a bit odd is......the two pieces are quite different in size.
If i can explain this......... suppose you have a 55mm Circular Polar. The threaded part is very close in diameter to the filter.
This Nikon......the filter piece has a much bigger diameter than the threaded piece.

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I have the same filter, for decades. I think Nikon was one of the few manufacturers who put a stop on it. It's a good way to know where the end and beginning of the movement are. Also, it helps remove the filter from the lens as the "stop" gives additional torque to use to unscrew it. That's my take on it. Don't know if those are the real reasons but they're easier to get off than my other filters with no stops and I can guestimate where I want to set the polarizing intensity.